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Re: Atomic operations in perl and Tk::IO

by hiseldl (Priest)
on Apr 01, 2003 at 15:03 UTC ( #247248=note: print w/ replies, xml ) Need Help??


in reply to Atomic operations in perl and Tk::IO

Update: <homer_simpson_voice>DOH! cloooosures</homer_simpson_voice>
-- I'll leave the text here so that no else who reads this makes the same mistake. :-)

In your call to component_window(), you assign $pcrh and $pid a la     my ($prch,$pid) = @_;
now, I don't see a shift nor a pop nor any other @_ manipulations, which makes your call to tail_lines() incorrect:

sub component_window { my ($prch,$pid) = @_; ... my $tail = Tk::IO->new( -linecommand => sub { tail_lines($prch, $_[0]) }); ... } sub tail_lines { my ($proc,$text) = @_; ... }
because $_[0] is the same as $prch when you call tail_lines($prch, $_[0]), and this seems to be not what you want.

You should be able to either pass the third element directly or get the third element in a var at the top of your sub (i.e.

sub component_window { my ($prch,$pid,$text)=@_; ...
and pass that...
... my $tail = Tk::IO->new( -linecommand => sub { tail_lines($prch, $text) }); ... }

--
hiseldl
What time is it? It's Camel Time!


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Re: Re: Atomic operations in perl and Tk::IO
by rinceWind (Monsignor) on Apr 01, 2003 at 15:18 UTC
    because $_[0] is the same as $prch when you call tail_lines($prch, $_[0]), and this seems to be not what you want.
    Sorry, hiseldl, you are not correct. The call to tail_lines is in an anonymous sub, which is a closure, which is passed a line of text by the Tk::IO mechanism.

    See Tk::IO for more details

      I've been writing Tk scripts for over a year now, and I temporarily forgot about closures as callbacks, oops, sorry. I'll leave the post as it is to maintain continuity of the thread and as a reminder to other's using Tk to watch for closures in the callbacks. :-)

      Cheers!

      --
      hiseldl
      What time is it? It's Camel Time!

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